This invention relates in general to devices for testing for presence of various gases and in particular to a new and useful test tube having a flame arrester for ensuring that the gases do not ignite.
A test tube of this nature is known from DE-GM 19 74 909.
For detecting various combustible gases with test tubes, cayalysts are introduced into the test tube to obtain reaction products, the presence of which can be demonstrated. These catalysts convert the gas to be detected, giving off considerable heat (for example, hydrogen with air oxygen in the presence of palladium or hopcalite). Other gases, as for instance, carbon bisulphide and hydrogen sulphide, indicate exothermic reactions with the test material in the indicator. In all these cases, high reaction temperatures can occur with high concentrations in the test tube. On exceeding a given concentration limit (lower explosion limit), the gas mixture becomes explosive so that there is the danger that the test tube with its high reaction temperatures becomes the ignition source.
From U.S. Pat. No. 4,159,304 a housing permitting through-flow for receiving a test tube is known. The known housing serves to protect the test tube from mechanical damage while being taken along by its carrier during working periods under difficult conditions, as they, for example, exist in factory installations. The known housing has connections for taking in a gas sample over a feed pump, so that the gas sample can stream through the test tube contained in the housing when the ends of the test tube are open. To detect the presence of any possible harmful substances in the gas sample, the housing can be screwed apart and the test tube taken out. Propagation into the environment of an ignition possibly caused by the test tube is not prevented by this measure.